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January 5, 2026
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STEVAL-MKI109D Software-Adjustable Power Circuitry

  • January 5, 2026
  • 1 reply
  • 261 views

Hi,

I'm trying to write custom firmware for the MKI109D. I am currently using an MKI251A adapter board with it for evaluation. How do I set VDD_DUT and VDDIO_DUT to 3.3V on the MKI109D board without using MEMS Studio?

 

mki109d_power_supply.png

 

Best answer by adomin1337

Hi,

Thank you for your response. I found that Vdd_set (PA4) and VddIO_set (PA5) can be configured as outputs from the dual-channel DAC. By programming the DAC, I am able to set the voltages on VDD_DUT and VDDIO_DUT as desired. Thanks!

-adomin1337

1 reply

Federica Bossi
Technical Moderator
January 9, 2026

Hi @adomin1337 ,

the VDD and VDDIO circuitry are set via micro. It is possible to use an application that communicates via virtual serial port (e.g. Termite) with STM32 and after that it is possible to send the command to communicate with all adapters included STEVAL-MKI251A. 

  • to change VDD supply voltage, the command to write is *set_vddaX.XXX
  • to change VDDIO supply voltage, the command to write is *set_vddioX.XXX

Please refer to STEVAL-MKI109D documentation (UM3420; for command list and description, chapter 4)

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adomin1337AuthorBest answer
Associate
January 12, 2026

Hi,

Thank you for your response. I found that Vdd_set (PA4) and VddIO_set (PA5) can be configured as outputs from the dual-channel DAC. By programming the DAC, I am able to set the voltages on VDD_DUT and VDDIO_DUT as desired. Thanks!

-adomin1337